An object information acquiring apparatus is used which includes a laser medium that oscillates laser light, an excitation source that excites the laser medium, a voltage accumulator that applies a voltage to the excitation source, a voltage supplier that supplies a voltage to the voltage accumulator, a voltage controller that limits a maximum supplied voltage from the voltage supplier, a receiver that receives a photoacoustic wave generated by an object irradiated with the laser light, and a constructor that acquires characteristic information relating to the object in use of the photoacoustic wave, wherein the voltage controller compares a measured voltage value obtained by implementing division of a supplied voltage from the voltage supplier with a reference voltage value defining the maximum supplied voltage.

A cascade control system of an optical fiber amplifier includes a target setting parameter module, a primary controller, at least one controlled module and a secondary controller corresponding to the controlled module. The control system adopts two or more cascade control loops so that disturbance entering into the secondary loop can be overcome quickly, thereby the dynamic characteristics of the system may be improved. The primary controller aims to coarse adjustment and overall target control, and the secondary controller aims to fine adjustment and quick convergence of a short-term target, so that the control quality of the cascade control system may be further improved. The cascade control system may define the overall control target directly in the primary loop and avoid impact of aging characteristics of some special parameters on the application.

The optical amplifier, which amplifies wavelength multiplexed signal light, comprises: a multi-core optical fiber which includes cladding and a first core and a second core disposed in the cladding, and which is doped with rare-earth ions; an excitation light source for supplying excitation light to the cladding of the multi-core optical fiber; and a wavelength demultiplexing means for separating the wavelength bands of the wavelength multiplexed signal light that has propagated through the first core. The signal light of a relatively long wavelength band among a plurality of wavelength bands separated by the wavelength demultiplexing means is caused to propagate through the second core, and is then multiplexed with the signal light of a relatively short wavelength band among the plurality of wavelength bands separated by the wavelength demultiplexing means, and the resultant multiplexed signal light is output.

The invention belongs to the field of lasers, more precisely to the field of constructional details of laser devices and laser devices for controlling intensity, frequency, length, polarization or direction of emitted rays. The present invention is an improved gain switched fiber laser, which enables changes of repetition frequency in a large range and which, at the same time, maintains a constant peak power and duration of generated laser pulses. The essence of the laser according to the invention is the pump system which is coupled to an oscillator and pumps the oscillator as well as the amplifier. The pump system comprises a primary and a secondary pump module, each at least with one pump laser diode, wherein the primary module generates short pump pulses and wherein the primary and secondary pump module operate at different peak powers. The power generated by the secondary module can be directly used to decrease the effect of active medium relaxation via spontaneous emission in-between laser pulses, which enables generation of short laser pulses on demand having constant parameters.

In one embodiment, a lidar system includes a light source configured to emit light at one or more wavelengths between 1200 nm and 1400 nm. The lidar system also includes a scanner configured to scan the emitted light across a field of regard of the lidar system and a receiver configured to detect a portion of the emitted light scattered by a target located a distance from the lidar system. The lidar system further includes a processor configured to determine the distance from the lidar system to the target based at least in part on a round-trip time for the portion of the emitted light to travel from the lidar system to the target and back to the lidar system.

Embodiments discussed herein refer to LiDAR systems and methods that enable substantially instantaneous power and frequency control over fiber lasers. The systems and methods can simultaneously control seed laser power and frequency and pump power and frequency to maintain relative constant ratios among each other to maintain a relatively constant excited state ion density of the fiber laser over time.

A device controller (16) for directing a drive current (12A) to a device (12) includes a current driven power source (40) that is electrically connected to the device (12); and a current adjuster (22) electrically connected to the power source (40) in parallel to the device (12). The current adjuster (22) selectively adjusts the drive current (12A) directed to the device (12). For a laser (12), the current adjuster (22) can adjust the drive current (12A) to modulate a center wavelength of an illumination beam (20) generated by the laser (12).

A control system includes a field-programmable gate array (FPGA), a digital-to-analog conversion (DAC) circuit, an external TEC driver, and a pump chip. The field-programmable gate array (FPGA) includes a pump driver and a thermoelectric-cooler (TEC) controller. The digital-to-analog conversion (DAC) circuit is coupled to the FPGA. The external TEC driver is external to the FPGA and coupled to the FPGA. The pump chip includes a pump and a TEC and is coupled to the DAC circuit and the external TEC driver.

A laser device includes at least one light source; a delivery fiber configured to propagate laser light launched from the light source; a monitor fiber optically coupled to the delivery fiber and configured to propagate a part of the light propagating in a direction opposite to a propagation direction of the laser light in the delivery fiber, and a light receiving unit configured to receive the light propagated by the monitor fiber. The light receiving unit is configured to detect first light included in a wavelength band of visible light.

The embodiments disclosed herein reduce numerous active regulators (e.g., to only one) used in previous circuits that require regulated current and still accomplish the current regulation provided to each load by means of an array of autotransformers, and if required, rectifiers, and filters. Therefore, in an exemplary embodiment, there is eliminated the numerous active regulators by replacing them with simple passive components and an active regulator.